In order to meet traffic demands of wireless data which has continuously increased, the wireless communication system has been developed for supporting a higher data transmission rate. Currently commercialized 4-th Generation (4G) systems are being developed mainly to improve spectral efficiency in order to increase a data transmission rate. However, it is difficult to satisfy increasing wireless data traffic demands only with improving frequency efficiency.
The use of a very wide frequency band has been considered. However, because a current mobile communication cellular system uses a frequency band of no more than 10 GHz, it is difficult to secure a wide frequency band. Accordingly, it is required to secure a broadband frequency in a higher frequency band. However, as a frequency for wireless communications increases, a wave path loss also increases. Accordingly, the wave propagation distance becomes shorter and the service coverage area decreases. In order to solve the problem, a beam forming technology has been suggested as an important technology for alleviating wave path loss and increasing a transfer distance of waves.
The beam forming technology may be classified into transmission beam forming performed at a transmission end and reception beam forming performed at a reception end. In general, the Tx beam forming increases directivity by concentrating a radio wave arrival area at a particular direction by using a plurality of antennas. Then, the form in which a plurality of antennas are provided may use an antenna array, and the antennas included in the antenna array may be referred to as array elements. The antenna array may be configured in various types such as a linear array and a planar array. If the transmission beam forming is used, transmission distance increases as a directionality of signals increases. Further, since the signal that is transmitted in another direction is reduced, signal interference for another receiving end significantly decreases.
Likewise, the transmission end also may perform beam forming on a received signal using a reception antenna array. The Rx beam forming concentrates reception of radio waves from a particular direction to increase received signal sensitivity incident from that corresponding direction and excludes signals incident from other directions to provide a gain of blocking an interference signal.
As described above, in order to secure a wide frequency band, an ultra-high frequency, that is, a millimeter wave system is expected to be introduced, in which case a beam forming technology for overcoming wave path loss is being considered. In a communication system to which a beam forming technology is applied, a transmitter selects an optimum transmission/reception beam and measures and feeds back channel information on the transmission/reception beam. Thus, measures for improving an operation of the transmitter in a communication system to which the beam forming technology is applied are required.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.